The "graphical horsepower" between the Xbox and PS3 isn't noticeable, both 720P low powered consoles by modern standards.
You have a couple of stand-outs like Halo 4 and Uncharted, but other than that, it's a wash graphically, both look absolutely terrible today.
Generally most developers go with the Unreal Engine, which started to show it's age badly during the early years of the generation, texture pop-in, poor lighting, poor textures, you name it. - Perfect example would be Mass Effect 3.
When a developer really works over the Unreal engine though, you can get some impressive stuff like Bioshock infinite on the PC, but that seems to be the exception not the norm.
Hopefully next generation more developers will decide to use something different like CryEngine.
If you are truly worried about Graphics though (I doubt anyone is if they are exclusively gaming on a console!), build a PC, whack it under your TV, use a controller with Steams big picture mode and enjoy the better graphics, framerates, networking, sound and the cheaper games.
www.youtube.com/@Pemalite
